SOME
FACTS ABOUT M.E./PVFS/CFS

In
the United Kingdom, CFS covers a number of conditions, including myalgic
encephalopathy (ME) also known as post viral fatigue syndrome (PVFS). The latter
is characterised by fatigability and slow recovery following minimal exertion,
marked fluctuations in the severity of symptoms throughout the day, impaired
circulation and the involvement of the CNS. Most patients who fulfil the British
criteria for CFS appear to have disorders other than ME including undiagnosed
hypothyroidism, masked depression, and problems related to lifestyle and
nutrition (e.g. deficiencies of vitamins D and B12). In
America, the stricter criteria devised by the CDC (1988, 1992) select a more
homogeneous population, so many cases of CFS so defined are probably the
equivalent of ME/PVFS.

The
prevalence of ME and strictly-defined CFS is about 1 per 1000; the prevalence of
CFS selected using the British criteria may be as high as 2%.

The
following papers generally refer to studies on ME/PVFS and strictly-defined CFS.

Research into
ME/PVFS/CFS has shown:

1.
The presence of enteroviral particles in a significant number of muscle biopsies
taken from ME/PVFS patients (e.g. Bowles et al, Gow et al). This was rare in
healthy controls. Enteroviral specific sequences have also been detected in the
serum of 41% of patients with post-infectious chronic fatigue (Clements et al).
The proportion of positive results was significantly higher than that found in
acutely ill patients with possible enteroviral disease (27%) and in healthy
controls (2%).

4.
Abnormalities in muscle function have been found in a subgroup and do not seem
to be related to inactivity (Lane et al). In people with ME, objective tests
have found prolonged recovery rates following exercise (Paul et al).

5.
MRI scans have revealed abnormalities in up to 80% of the patients in one study
(Daugherty et al). According to researchers, these defects are probably caused
by chronic viral encephalitis. There was a correlation between the areas
involved and the symptoms experienced. Abnormalities on SPECT scans provide
further objective evidence of CNS dysfunction. Studies published to date show
patterns of reduced blood flow which are markedly different from those
documented in major depression (Costa et al). Moreover, the number of defects
are correlated with clinical status (e.g. Schwartz et al).

6.
Enteroviral sequences have been detected in tissue samples taken from the
hypothalamus and brain stem of a patient with ME. Such sequences were not found
in samples from depressed patients who had not suffered from ME.

7.
Several studies have found evidence of an overactive immune system. The
abnormalities are generally more common in the severely affected, and are
consistent with a persisting viral infection. The disturbances of cell-mediated
immunity in patients with ME and CFS differ in prevalence and magnitude from
those which have been observed in people suffering from major depression (e.g.
Lloyd et al). There is also growing evidence implicating HHV-6 (e.g. Ablashi et
al).

8.
Some symptoms of CFS may be related to due to an inflammatory process. Findings
from experiments in mice are consistent with the notion that fatigue could be
due to "cytokine production within the CNS".

9.
Research has revealed a number of disturbances in the function of the
hypothalamic-pituitary-adrenal axis. Some of these are different from the
abnormalities documented in patients suffering from depression (e.g. Demitrack
et al, Scott et al).

10.
Neuropsychological tests on patients with ME/PVFS and strictly-defined CFS have
revealed abnormalities which are consistent with an organic brain disorder (e.g.
Daugherty et al). The deficits have been found in both community and hospital
samples and they were not the result of psychiatric disorders, such as
depression (e.g. Smith, DeLuca et al).

Scholey,
A., McCue, P and Wesnes, KA. A comparison of the cognitive deficits seen
in myalgic encephalomyelitis to Alzheimer's Disease. Proceedings of the
British Psychological Society, 1999, January, 12.

11.
The depression experienced by patients with ME/PVFS and strictly defined CFS is
different from that reported by psychiatric patients and closely related to the
severity of the other symptoms. Some patients report more anxiety (Lindal et
al).

14.
The fatigue reported by patients with ME/PVFS and strictly-defined CFS is very
different from that experienced by the general population. Scores on fatigue
scales are more like those of people with M.S.

16.
Recent evidence indicates that most patients with CFS do not spend the whole of
the daytime resting. A number of coping strategies are used, some of which are
associated with a positive outcome (e.g. Saltzstein et al).

17.
Longitudinal studies using appropriate measures have shown that physical
attributions do not affect outcome (e.g. Lawrie et al). Moreover, research on
patients with ME indicated that a belief in a biological cause was not
associated with avoidance behaviour or poor mental health.

18.
Exercise does not lead to a major reduction in activity levels (Sisto et al, Van
der Werf et al). There is no evidence for the phobic avoidance of activity
amongst the majority of patients with CFS, or support for the view that
deconditioning plays a major role in the perpetuation of fatigue (Bazelmans et
al, Sargent et al).

19.
Graded exercise, where activity is increased according to a plan irrespective of
symptoms, is not appropriate for all patients with CFS (Friedberg and Krupp,
Jason et al). Indeed, overexertion can lead to relapse (eg Lapp). Although
cognitive behavioural therapy is not superior to counselling for CFS in general
(Ridsdale et al), it may be helpful for a subgroup, for example, those who are
particularly anxious and depressed, those with inadequate coping strategies or
where activity levels are largely determined by a fear of symptom flare-ups.
Follow-up studies suggest that improvements are often limited and transient
(e.g. Akagi et al). There are no follow-up studies indicating benefits for those
with somatic symptoms (cf. Deale et al).

21.
CFS remains a research diagnosis. A number of subgroups have been identified.
These appear to have different causes, different rates of psychiatric disorders,
may have different prognoses and probably require different treatments.

22.
The documented links between CFS and psychiatric disorders may reflect the use
of broader diagnostic criteria and the researcher's choice of measures. More
psychiatric morbidity is diagnosed using the DIS than the SCID.

Gilliam,
AG. Epidemiological study of an epidemic, diagnosed as poliomyelitis,
occurring among the personnel of the Los Angeles County General Hospital during
the Summer of 1934. Public Health Bulletin, US Treasury Dept. no. 240.
Washington: United States Government Printing Office 1938.

Komaroff,
AL et al. Health status in patients with chronic fatigue syndrome and in
general population and disease comparison groups. American Journal of Medicine,
1996, 101, 3, 281-290. (This shows that the level of disability associated with
CFS is higher than that documented in several medically-ill groups).

Levine,
S et al. Prevalence of IgM and IgG antibody to HHV-6 and HHV‑8 and
results of plasma PCR to HHV-6 and HHV-7 in a group of CFS patients and healthy
donors. Journal of Chronic Fatigue Syndrome, 2001, 9, 1/2, 31-40.

Suggested
criteria for ME (based on the work of Dr MA Ramsay):

2.
Neurological disturbances and variable involvement of cardiac and other bodily
systems.

3.
Impaired circulation.

4.
Marked variability of symptoms in the course of a day and from day to day.

5.
An extended relapsing course with a tendency to chronicity.

ME
can be diagnosed immediately. For research purposes however, a minimum duration
of six months may help to differentiate ME from more common, transient
post-viral syndromes.

The
criteria for ME differ from the American and Oxford definitions for CFS in three
ways. Firstly, the latter do not require evidence of central nervous system
dysfunction. Secondly, they do not include any references to the fluctuation of
symptoms or the close links between symptoms and exertion. Thirdly, the older
CDC criteria place a much greater emphasis on infection-related symptoms such as
mild fever, sore throat (which are counted twice) and tender glands compared to
the definitions of ME.

11. ME/PVFS occurs
both sporadically and in epidemics. However, there have been no
documented epidemics of depression.

12. Research showing
that CFS patients resemble people with MS more than a depressed group
in terms of personality disturbance and trait neuroticism suggests
that "CFS cannot be explained as a form of depression with
predominantly somatic symptoms".